Earnings per share - Calculation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Aug. 31, 2021	Aug. 31, 2020	Aug. 31, 2021	Aug. 31, 2020
Earnings Per Share [Abstract]
Net income	$ 30,976	$ 23,977	$ 63,494	$ 62,061
Weighted average shares outstanding (in shares)	43,762	45,036	43,896	44,941
Dilutive impact from common stock equivalents (in shares)	740	328	646	441
Diluted weighted average shares outstanding (in shares)	44,502	45,364	44,542	45,382
Basic earnings per share (in dollars per share)	$ 0.71	$ 0.53	$ 1.45	$ 1.38
Diluted earnings per share (in dollars per share)	$ 0.70	$ 0.53	$ 1.43	$ 1.37